Function Documentation

The acos() function computes the principal value of the arc cosine of __x. The returned value is in the range [0, pi] radians. A domain error occurs for arguments not in the range [-1, +1].

double asin

(

double

__x

)

The asin() function computes the principal value of the arc sine of __x. The returned value is in the range [-pi/2, pi/2] radians. A domain error occurs for arguments not in the range [-1, +1].

double atan

(

double

__x

)

The atan() function computes the principal value of the arc tangent of __x. The returned value is in the range [-pi/2, pi/2] radians.

double atan2

(

double

__y,

double

__x

)

The atan2() function computes the principal value of the arc tangent of __y / __x, using the signs of both arguments to determine the quadrant of the return value. The returned value is in the range [-pi, +pi] radians.

The fabs() function computes the absolute value of a floating-point number __x.

double fdim

(

double

__x,

double

__y

)

The fdim() function returns max(__x - __y, 0). If __x or __y or both are NaN, NaN is returned.

double floor

(

double

__x

)

The floor() function returns the largest integral value less than or equal to __x, expressed as a floating-point number.

double fma

(

double

__x,

double

__y,

double

__z

)

The fma() function performs floating-point multiply-add. This is the operation (__x * __y) + __z, but the intermediate result is not rounded to the destination type. This can sometimes improve the precision of a calculation.

double fmax

(

double

__x,

double

__y

)

The fmax() function returns the greater of the two values __x and __y. If an argument is NaN, the other argument is returned. If both arguments are NaN, NaN is returned.

double fmin

(

double

__x,

double

__y

)

The fmin() function returns the lesser of the two values __x and __y. If an argument is NaN, the other argument is returned. If both arguments are NaN, NaN is returned.

The frexp() function breaks a floating-point number into a normalized fraction and an integral power of 2. It stores the integer in the int object pointed to by __pexp.

If __x is a normal float point number, the frexp() function returns the value v, such that v has a magnitude in the interval [1/2, 1) or zero, and __x equals v times 2 raised to the power __pexp. If __x is zero, both parts of the result are zero. If __x is not a finite number, the frexp() returns __x as is and stores 0 by __pexp.

Note

This implementation permits a zero pointer as a directive to skip a storing the exponent.

double hypot

(

double

__x,

double

__y

)

The hypot() function returns sqrt(__x*__x + __y*__y). This is the length of the hypotenuse of a right triangle with sides of length __x and __y, or the distance of the point (__x, __y) from the origin. Using this function instead of the direct formula is wise, since the error is much smaller. No underflow with small __x and __y. No overflow if result is in range.

static int isfinite

(

double

__x

)

static

The isfinite() function returns a nonzero value if __x is finite: not plus or minus infinity, and not NaN.

int isinf

(

double

__x

)

The function isinf() returns 1 if the argument __x is positive infinity, -1 if __x is negative infinity, and 0 otherwise.

Note

The GCC 4.3 can replace this function with inline code that returns the 1 value for both infinities (gcc bug #35509).

The log10() function returns the logarithm of argument __x to base 10.

long lrint

(

double

__x

)

The lrint() function rounds __x to the nearest integer, rounding the halfway cases to the even integer direction. (That is both 1.5 and 2.5 values are rounded to 2). This function is similar to rint() function, but it differs in type of return value and in that an overflow is possible.

Returns

The rounded long integer value. If __x is not a finite number or an overflow was, this realization returns the LONG_MIN value (0x80000000).

long lround

(

double

__x

)

The lround() function rounds __x to the nearest integer, but rounds halfway cases away from zero (instead of to the nearest even integer). This function is similar to round() function, but it differs in type of return value and in that an overflow is possible.

Returns

The rounded long integer value. If __x is not a finite number or an overflow was, this realization returns the LONG_MIN value (0x80000000).

double modf

(

double

__x,

double *

__iptr

)

The modf() function breaks the argument __x into integral and fractional parts, each of which has the same sign as the argument. It stores the integral part as a double in the object pointed to by __iptr.

The round() function rounds __x to the nearest integer, but rounds halfway cases away from zero (instead of to the nearest even integer). Overflow is impossible.

Returns

The rounded value. If __x is an integral or infinite, __x itself is returned. If __x is NaN, then NaN is returned.

int signbit

(

double

__x

)

The signbit() function returns a nonzero value if the value of __x has its sign bit set. This is not the same as `__x < 0.0', because IEEE 754 floating point allows zero to be signed. The comparison `-0.0 < 0.0' is false, but `signbit (-0.0)' will return a nonzero value.